Low-cost large-screen wide-angle fast-response liquid crystal display apparatus

ABSTRACT

The present invention discloses a super large wide-angle high-speed response liquid crystal display apparatus manufactured by using a photolithographic procedure for three times. The invention adopts a halftone exposure technology to form a gate electrode, a common electrode, a pixel electrode and a contact pad, and then uses the halftone exposure technology to form a silicon (Si) island and a contact hole, and a general exposure technology to form a source electrode, a drain electrode and an orientation control electrode. A passivation layer uses a masking deposition method. A film is formed by using a P-CVD method, or a protective area is formed at a local area by using an ink coating method or spray method, and a TFT array substrate used for the super large wide-angle high-speed response liquid crystal display apparatus manufactured by using a photolithographic procedure for three times can be produced.

RELATED APPLICATIONS

This application is a divisional application claiming priority to Ser.No. 11/743,749, filed on May 3, 2007.

FIELD OF THE INVENTION

The present invention relates to a large-screen wide-angle liquidcrystal display apparatus manufactured by using a halftone exposuremethod.

BACKGROUND OF THE INVENTION

In multi-domain vertical alignment (MVA) liquid crystal displayapparatuses, an orientation control electrode for controlling analignment of a liquid crystal molecule has been disclosed in Japan LaidOpen Patents Nos. 07-230097, 11-109393 and 2001-042347.

SUMMARY OF THE INVENTION

In view of the shortcomings of the prior art, the inventor of thepresent invention based on years of experience in the related industryto conduct researches and experiments, and finally developed alarge-screen wide-angle liquid crystal display apparatus in accordancewith the present invention to overcome the foregoing shortcomings.

Therefore, it is a primary objective of the present invention to adopt aprior art orientation control electrode of an LCD panel structure tocorrespond to smaller pixels. Since only one type of orientation controlelectrode is used only, and the edge field effect of a pixel electrodeis adopted, therefore it is not applicable for lager pixels.

At present, the mainstream of multi-domain vertical alignment (MVA)liquid crystal display apparatus generally uses a bump or slit electrodefor the alignment control of the sides of a color filter (CF) substrate,and this method can make a proper alignment if the pixel is large, butthe cost of CF substrates is high, and becomes an obstacle formanufacturing a large-screen liquid crystal TV by a low cost.

Therefore, it is a primary objective of the present invention to reducethe number of photolithographic procedures of the TFT active matrixsubstrate and the CF substrate during the manufacture of the TFT activematrix liquid crystal display apparatus, in order to shorten themanufacturing procedure, lowering the manufacturing cost, and improvingthe yield rate.

The technical measures taken by the present invention are described asfollows.

In Measure 1, unstable and swinging discrimination lines are avoided,and two types of orientation control electrodes are installed at anupper layer of a pixel electrode through an insulating film, and betweencommon electrodes corresponding to the pixel electrodes. With theforegoing two different types of orientation control electrodes, theoblique direction of anisotropic liquid crystal molecules having anegative dielectric constant can be controlled precisely.

In Measure 2, one type of orientation control electrode is installed atan upper layer of a pixel electrode through an insulating film, and aslender slit is formed in the pixel electrode, and these two alignmentcontrol mechanisms can control the oblique direction of anisotropicliquid crystal molecules having a negative dielectric constantprecisely.

In Measure 3, the orientation control electrodes as used in Measures 1and 2 is connected to the pixel electrodes as closer to the substrate aspossible.

In Measure 4, the alignment control mechanisms as used in Measures 1 and2 provides four perfect area alignments for a curvature of 90 degrees ata position proximate to the center of the pixel.

In Measure 5, a halftone exposure method is introduced into themanufacturing process of the TFT array substrate to reduce the number ofphotolithographic procedures.

In Measure 6, a basic unit pixel is divided into two sub pixels, and thecommon electrodes are installed parallelly on a video signal line, andthe common electrodes of odd-numbered rows and even-numbered rows switchsignals with different polarities in each scan period, and producedifferent voltages applied to the liquid crystal molecules of the twosub pixels.

With Measures 1 and 2, the TFT array substrate has all alignment controlfunctions, and thus it is not necessary to form a pad or slit on the CFsubstrate for the alignment control, so that the MVA LCD panel can bemanufactured with a low-cost CF substrate to lower the cost and improvethe yield rate.

With Measure 3, the orientation control electrode connected to the pixelelectrode is proximate to the substrate for enhancing the rotationaltorque of an electric field of anisotropic liquid crystal moleculeshaving negative dielectric constant and acted at the vertical alignment,so as to achieve a high-speed response.

With Measure 4, unnecessary discrimination lines can be avoided toimprove the overall light transmission rate of the screen and reduceunevenness of the LCD panel.

With Measures 1, 2 and 5, the processing costs for both CF substrate andTFT array substrate can be lowered, and thus the manufacturing cost ofMVA LCD panels can be lowered significantly; the production efficiencycan be improved, and the yield rate can be enhanced.

With Measures 5 and 6, the liquid crystal alignment control mechanismcan be manufactured by a very simple manufacturing process, and thecorrection of γ curve can be achieved by a very simple circuit, and thusa little cost is incurred for enhancing the display quality of a MVAliquid crystal display apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a conventional MVA LCD panel;

FIG. 2 is a cross-sectional view of a conventional MVA LCD panel;

FIG. 3 is a cross-sectional view of a MVA LCD panel of the presentinvention;

FIG. 4 is a cross-sectional view of a MVA LCD panel of the presentinvention;

FIG. 5 is a schematic view of the principle of a MVA LCD panel of thepresent invention;

FIG. 6 is a schematic view of the principle of a MVA LCD panel of thepresent invention;

FIG. 7 is a schematic view of the principle of a MVA LCD panel of thepresent invention;

FIG. 8 is a cross-sectional view of a MVA LCD panel adopting a TFTmatrix substrate in accordance with the present invention;

FIG. 9 is a cross-sectional view of a TFT array substrate used for a MVALCD panel in accordance with the present invention;

FIG. 10 is a cross-sectional view of a TFT array substrate used for aMVA LCD panel in accordance with the present invention;

FIG. 11 is a cross-sectional view of a TFT array substrate used in a MVALCD panel in accordance with the present invention;

FIG. 12 is a cross-sectional view of a TFT array substrate used in a MVALCD panel in accordance with the present invention;

FIG. 13 is a cross-sectional view of a TFT array substrate used in a MVALCD panel in accordance with the present invention;

FIG. 14 is a cross-sectional view of a TFT array substrate used in a MVALCD panel in accordance with the present invention;

FIG. 15 is a cross-sectional view of a TFT array substrate used in a MVALCD panel in accordance with the present invention;

FIG. 16 is a cross-sectional view of a TFT array substrate used in a MVALCD panel in accordance with the present invention;

FIG. 17 is a cross-sectional view of a TFT array substrate used in a MVALCD panel in accordance with the present invention;

FIG. 18 is a cross-sectional view of a TFT array substrate used in a MVALCD panel in accordance with the present invention;

FIG. 19 is a cross-sectional view of a TFT array substrate used in a MVALCD panel in accordance with the present invention;

FIG. 20 is a cross-sectional view of a TFT array substrate used in a MVALCD panel in accordance with the present invention;

FIG. 21 is a cross-sectional view of a TFT array substrate used in a MVALCD panel in accordance with the present invention;

FIG. 22 is a cross-sectional view of a TFT array substrate used in a MVALCD panel in accordance with the present invention;

FIG. 23 is a cross-sectional view of a TFT array substrate used in a MVALCD panel in accordance with the present invention;

FIG. 24 is a planar view of a TFT array substrate used in a MVA LCDpanel in accordance with the present invention;

FIG. 25 is a planar view of a TFT array substrate used in a MVA LCDpanel in accordance with the present invention;

FIG. 26 is a planar view of a TFT array substrate used in a MVA LCDpanel in accordance with the present invention;

FIG. 27 is a planar view of a TFT array substrate used in a MVA LCDpanel in accordance with the present invention;

FIG. 28 is a planar view of a TFT array substrate used in a MVA LCDpanel in accordance with the present invention;

FIG. 29 is a planar view of a TFT array substrate used in a MVA LCDpanel in accordance with the present invention;

FIG. 30 is a planar view of a TFT array substrate used in a MVA LCDpanel in accordance with the present invention;

FIG. 31 is a planar view of a TFT array substrate used in a MVA LCDpanel in accordance with the present invention;

FIG. 32 shows a circuit model of a TFT array substrate of field-orderdriven MVA LCD panel in accordance with the present invention;

FIG. 33 shows a relation between the brightness and the signal voltageapplied to a MVA LCD panel as depicted in FIG. 32;

FIG. 34 is a waveform diagram of a MVA LCD panel as depicted in FIG. 21;

FIG. 35 shows a circuit model of a TFT array substrate that is dividedinto upper and lower field-order driven MVA LCD panels in accordancewith the present invention;

FIG. 36 illustrates a field-order driving method that divides a screeninto upper and lower sections and writes data from the center of thescreen to the upper or lower section of the screen in accordance withthe present invention;

FIG. 37 illustrates a field-order driving method that divides a screeninto upper and lower sections and writes data from the upper or lowersections of the screen towards the center of the screen in accordancewith the present invention;

FIG. 38 illustrates a field-order driving method that divides a screeninto upper and lower sections and writes data from the center of thescreen to the upper or lower section of the screen in accordance withthe present invention;

FIG. 39 illustrates a field-order driving method that divides a screeninto upper and lower sections and writes data from the upper or lowersections of the screen towards the center of the screen in accordancewith the present invention;

FIG. 40 is a cross-sectional view of a basic unit pixel of a TFT arraysubstrate of a horizontal electric field LCD panel in accordance withthe present invention;

FIG. 41 is a cross-sectional view of a basic unit pixel of a TFT arraysubstrate of a horizontal electric field LCD panel in accordance withthe present invention;

FIG. 42 is a cross-sectional view of a basic unit pixel of a TFT arraysubstrate of a horizontal electric field LCD panel in accordance withthe present invention;

FIG. 43 is a cross-sectional view of a basic unit pixel of a TFT arraysubstrate of a horizontal electric field LCD panel in accordance withthe present invention;

FIG. 44 is a cross-sectional view of a basic unit pixel of a TFT arraysubstrate of a horizontal electric field LCD panel in accordance withthe present invention;

FIG. 45 is a cross-sectional view of a basic unit pixel of a TFT arraysubstrate of a horizontal electric field LCD panel in accordance withthe present invention;

FIG. 46 shows a circuit model of a circuit of a TFT array substrate of afield-order driven horizontal electric field LCD panel in accordancewith the present invention;

FIG. 47 is a cross-sectional view of a TFT array substrate of ahorizontal electric field LCD panel in accordance with the presentinvention;

FIG. 48 is a cross-sectional view of a TFT array substrate of ahorizontal electric field LCD panel in accordance with the presentinvention;

FIG. 49 is a planar view of a TFT array substrate of a horizontalelectric field LCD panel in accordance with the present invention;

FIG. 50 is a planar view of a TFT array substrate of a horizontalelectric field LCD panel in accordance with the present invention;

FIG. 51 is a planar view of a TFT array substrate of a horizontalelectric field LCD panel in accordance with the present invention;

FIG. 52 is a planar view of a TFT array substrate of a horizontalelectric field LCD panel in accordance with the present invention;

FIG. 53 is a planar view of a TFT array substrate of a horizontalelectric field LCD panel in accordance with the present invention;

FIG. 54 is a planar view of a TFT array substrate of a horizontalelectric field LCD panel in accordance with the present invention;

FIG. 55 is a waveform diagram of a horizontal electric field LCD panelas depicted in FIG. 54;

FIG. 56 shows a circuit model of a TFT array substrate of a field-orderdriven horizontal electric field LCD panel that divides a display screeninto upper and lower sections in accordance with the present invention;

FIG. 57 is a cross-sectional view of a basic unit pixel of a TFT arraysubstrate of a MVA LCD panel in accordance with the present invention;

FIG. 58 is a cross-sectional view of a basic unit pixel of a TFT arraysubstrate of a MVA LCD panel in accordance with the present invention;

FIG. 59 is a cross-sectional view of a basic unit pixel of a TFT arraysubstrate of a MVA LCD panel in accordance with the present invention;

FIG. 60 is a cross-sectional view of a basic unit pixel of a TFT arraysubstrate of a MVA LCD panel in accordance with the present invention;

FIG. 61 is a cross-sectional view of a manufacturing flow that adopts ahalftone exposure method to form a contact pad for a pixel electrode inaccordance with the present invention;

FIG. 62 is a cross-sectional view of a manufacturing flow that adopts ahalftone exposure method to form a contact pad for a pixel electrode inaccordance with the present invention;

FIG. 63 is a cross-sectional view of a manufacturing flow that adopts ahalftone exposure method to give an island effect to a semiconductorlayer of a thin film transistor component and form a contact hole inaccordance with the present invention;

FIG. 64 is a cross-sectional view of a manufacturing flow that forms asource electrode, a drain electrode, a terminal electrode, and combcommon electrode in accordance with the present invention;

FIG. 65 is a cross-sectional view of a flow of manufacturing a thin filmtransistor substrate by a halftone exposure method in accordance withthe present invention;

FIG. 66 illustrates the structure of a horizontal electric field activematrix substrate at a center pixel common electrode of the center of abasic unit pixel;

FIG. 67 illustrates a masking principle of a halftone exposure appliedin the present invention;

FIG. 68 illustrates the principle of a halftone multiple exposure methodapplied in the present invention;

FIG. 69 illustrates a first photolithographic procedure that needs toalign at a mark when using a halftone multiple exposure method inaccordance with the present invention;

FIG. 70 illustrates the principle of aligning with a mark by a halftonemultiple exposure method that uses a pulse laser in a glass substrate inaccordance with the present invention;

FIG. 71 is a cross-sectional view of a manufacturing flow of using ahalftone exposure method to form a thin film transistor substrate inaccordance with the present invention;

FIG. 72 is a cross-sectional view of a manufacturing flow of using ahalftone exposure method to form a scan line portion, a pixel electrodeand a terminal portion of a thin film transistor substrate in accordancewith the present invention;

FIG. 73 shows a cross-sectional view of a manufacturing flow of using ahalftone exposure method to give an island effect to a semiconductorlayer of a thin film transistor component and expose a pixel electrodeand a terminal portion completely;

FIG. 74 shows a cross-sectional view of a manufacturing flow beforeforming a source electrode and a drain electrode in the process ofmanufacturing a thin film transistor component as illustrated in FIGS.73 and 74;

FIG. 75 is cross-sectional view of the structure forming a TFT arraysubstrate of an orientation control electrode connected to a scan lineand disposed on the previously formed pixel electrode;

FIG. 76 is a planar view of a TFT array substrate as depicted in FIG.75;

FIG. 77 is a cross-sectional view of forming a vertical alignment cellof one type of orientation control electrode connected to a commonelectrode and disposed on the previously formed pixel electrode;

FIG. 78 is a cross-sectional view of a vertical alignment cell of onetype of orientation control electrode connected to a pixel electrode anddisposed on the previously formed plate electrode;

FIG. 79 is a cross-sectional view of a structure of forming only onetype of orientation control electrode on a pixel electrode of thepreviously formed TFT array substrate;

FIG. 80 is a cross-sectional view of a structure of forming only onetype of orientation control electrode on a pixel electrode of thepreviously formed TFT array substrate;

FIG. 81 is a cross-sectional view of a structure of forming only onetype of orientation control electrode on a pixel electrode of thepreviously formed TFT array substrate;

FIG. 82 illustrates a manufacturing flow of performing thephotolithographic procedure for three times that uses a MVA TFT arraysubstrate to apply a halftone exposure method for two times;

FIG. 83 illustrates a manufacturing flow of performing thephotolithographic procedure for three times that uses a MVA TFT arraysubstrate to apply a halftone exposure method for two times;

FIG. 84 illustrates a manufacturing flow of performing thephotolithographic procedure for three times that uses an IPS TFT arraysubstrate to apply a halftone exposure method for three times; and

FIG. 85 illustrates a manufacturing flow of performing thephotolithographic procedure for three times that uses an IPS TFT arraysubstrate to apply a halftone exposure method for three times.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

To make it easier for our examiner to understand the objective,innovative features and performance of the present invention, we use apreferred embodiment and the accompanying drawings for a detaileddescription of the present invention.

Referring to FIGS. 1 and 2 for cross-sectional views of a currentmainstream MVA LCD panel, a mechanism for controlling the direction ofmovements both is installed separately on upper and lower substrates tocontrol the vertical alignment of anisotropic liquid crystal moleculesof a negative dielectric constant. Since the discrimination line of anLCD panel using this method is constant without swinging, thereforeuneven display rarely occurs, and LCD panels with high quality ofdisplay can be produced at a good yield rate. However, it is necessaryto form a slit or a bump disposed on a lateral side of a CF substratecorresponding to a TFT substrate for the structure as shown in FIGS. 1and 2 to control the liquid crystal alignment, and the production costof the CF substrate is higher than that of the TN CF substrate. To lowerthe cost of the CF substrate, all liquid crystal alignment controlfunctions are built in the TFT substrate side.

Referring to FIGS. 75 to 81 for an embodiment of a CF substrate sidehaving no alignment control function as disclosed in the previouspatents, these CF substrates cannot be used as large substrates. Theseprior arts can be used for small pixels only. Since an edge field effectof a pixel electrode is used, therefore these substrates are notappropriate for the large pixel electrodes used for the liquid crystalTV.

With the two basic structures as shown in FIGS. 3 and 4, a TFT substrateside has all of the liquid crystal alignment control functions. In theTFT substrate side as shown in FIG. 3, two different liquid crystalorientation control electrodes are installed between the commonelectrode of the substrate and corresponding to the pixel electrode tosuccessfully form an equal-potential distribution as shown in FIG. 5. InFIG. 4, one type of orientation control electrode is installed on apixel electrode at the TFT substrate side and between the slit foralignment control and the pixel electrode corresponding to the commonelectrode of the substrate to successfully from an equal-potentialdistribution as shown in FIG. 6. Even for a structure as shown in FIG. 7instead of the structure as shown in FIG. 6, the similar equal-potentialdistribution an be formed successfully.

From FIGS. 5 to 7, a liquid crystal orientation control electrodeconnected to a pixel electrode is installed at an upper layer of thepixel electrode. The closer the distance from the common electrode ofthe CF substrate, the more similar is the equal-potential distributiondiagram of the pixel electrode through another type of liquid crystalorientation control electrode formed by an insulating film. Since theliquid crystal orientation control electrode not connected to the pixelelectrode yet is connected to a common electrode same potential of thecorresponding substrate.

If a cell gap is greater than 5 nm, the structure of a pixel electrodeof a TFT substrate connected to the liquid crystal orientation controlelectrode in accordance with the present invention almost has no effect.However, if the cell gap is below 3 nm, the effect is significant. Ifthe cell gap is below 2.5 nm, a sufficiently equal-potentialdistribution diagram is formed for controlling the alignment of liquidcrystal molecules.

Referring to FIGS. 24 and 26 for planar views of Embodiment 1 of a TFTsubstrate, two types of different orientation control electrodes areformed at an upper layer of a pixel electrode, and an orientationcontrol electrode installed at the middle of a pixel is coupled to agate electrode and installed parallel with a common electrode. Anotherorientation control electrode with a different alignment control ispassed and disposed at a contact pad in the pixel electrode and coupledto the pixel electrode. Referring to FIGS. 57 and 59 for across-sectional view of Embodiment 1 of the present invention, theheight of orientation control electrode of the pixel electrode isincreased to get closer to the common electrode of the substrate as muchas possible.

Referring to FIGS. 8, 9 and 11 for cross-sectional views a TFT portionas depicted in FIGS. 20, 24 and 26 respectively, the pixel electrodemust be installed at a lower layer to form a liquid crystal orientationcontrol electrode at an upper layer of the pixel electrode in accordancewith the present invention, and thus its characteristic resides on thatthe photolithographic procedure is used for producing a pixel electrode.FIG. 8 shows a process of using the photolithographic procedure forthree times as depicted in FIG. 82. To shorten the manufacturingprocess, the present invention adopts a halftone exposure method,characterized in that an exposure method as shown in FIGS. 67 and 68 isused for producing two or more types of posiresist thicknesses after theimage is developed.

In the first of the three times of photolithographic procedure as shownin FIG. 82, a gate electrode, a pixel electrode, a common electrode anda contact pad in a pixel electrode are formed. In the first procedure,two manufacturing processes exist as shown in FIGS. 61 and 62, andeither one of the two manufacturing processes can be used for formingthe pixel electrode, but it is preferable to select a shorter process asshown in FIG. 61. If the thickness of the orientation control electrodeas shown in FIG. 9 is reduced, and the halftone exposure method is usedin the third time photolithographic procedure, it is preferable toselect the process as shown in FIG. 62.

Since aluminum alloy is used for making a scan line (or a gateelectrode) in this invention, therefore ITO cannot be used in the pixelelectrode, because a partial battery reaction will result, and theabnormal corrosion or ITO blackening issues usually occur. As a result,the pixel electrode is generally a transparent electrode made of a thinfilm oxide such as titanium nitride or zirconium nitride.

The nitride of the transparent pixel electrode and the P—SiNxo of thegate insulating film cannot have a large selectivity for creating acontact hole by a y etching method, and the manufacturing processes ofthe previous embodiments as shown in FIGS. 72 to 74 cannot be usedanymore. To solve this problem, the present invention uses an aluminumalloy series contact pad to solve the aforementioned problem.

In the second time of the photolithographic procedure, the thin filmsemiconductor components are separated and the contact hole is formed,and this procedure is illustrated in FIG. 63. Since this procedure alsoadopts the halftone exposure method, therefore the procedure of thefirst time can be used for performing two operations. The processadopted in FIGS. 11 and 26 is a halftone exposure process other thanthat adopted in FIG. 82, and the halftone exposure method as illustratedin FIG. 65 is used for separating the thin film semiconductor componentswhile forming a source electrode and a drain electrode. The halftoneexposure process as shown in FIG. 65 is very similar to the halftoneexposure process as shown in FIG. 71, but the halftone exposure processas shown in FIG. 65 is more difficult to take place. When a positivephoto-resist layer at a thin area is removed by an oxygen plasma methodin the foregoing embodiment as shown in FIG. 71, sidewalls of a thinfilm semiconductor layer are oxidized, and the oxidization takes placeeasily at the time of removing an ohmic contact layer (n+a−siliconlayer) of a channel portion of the thin film transistor component, butan even removal cannot be achieved. In the situation as shown in FIG.65, the thin film semiconductor layer is protected by a metal barrierlayer completely when the positive photo-resist layer at the thin areais removed by the oxygen plasma method, and thus the oxidization almostwill not take place at the sidewalls.

In the third photolithographic procedure as shown in FIG. 82, anexposure method is generally used for forming a source electrode, adrain electrode and an orientation control electrode as shown in FIG. 8.In FIG. 9, the third photolithographic procedure also adopts aphotolithographic procedure that uses a halftone exposure method asshown in FIG. 64.

In FIGS. 8, 9 and 20, the third photolithographic procedure is used forforming two different types of orientation control electrodes at anupper layer of the pixel electrode through the insulating film. In FIG.11, a fourth photolithographic procedure is used for forming twodifferent types of orientation control electrodes, such that an obliquedirection of vertical alignment negative dielectric constant anisotropicliquid crystal molecules as shown in FIGS. 3 and 5.

In FIGS. 8, 9 and 20, a passivation film is a P—SiNx film formedpartially by using a CVD method. An ink-jet printing method or a plateoffset printing method is sued to coat a passivation film made of anorganic compound such as BCB. The shortcoming of the process shown inFIG. 11 resides on that a short circuit may occur easily at the commonelectrode of the corresponding substrate when two different types oforientation control electrodes are formed on the passivation film.

Referring to FIGS. 25 and 27 for planar views of Embodiment 2 of TFTsubstrate in accordance with the present invention, a slit is formed onthe pixel electrode for the alignment control, and a liquid crystalalignment control electrode connected to the pixel electrode is formedat an upper layer of the pixel electrode through the insulating film.Referring to FIGS. 58 and 60 for cross-sectional views of Embodiment 2of a pixel, Embodiment 2 similar to Embodiment 1 also installs theorientation control electrode connected to the pixel electrode at aposition proximate to the substrate, and thus its characteristic resideson that each type of electrodes and semiconductor layers is installed ata lower layer of the orientation control electrode.

Embodiments 1 and 2 of the present invention include all alignmentcontrol functions at the TFT substrate side. Compared with the previousmethods as shown in FIGS. 1 and 2, the methods adopted by the presentinvention as shown in FIGS. 3 and 4 also have the existing short-circuitproblem at the same layer of a video signal line while the orientationcontrol electrode is being formed. Therefore, the pixel structures asshown in FIGS. 24 to 27 are avoided, and a structure having a curvatureof 90 degrees at the center of the pixel is used instead. The videosignal line and the orientation control electrode of this structure arearranged in parallel and equidistantly with each other, so as to reducethe chance of having a short circuit.

Referring to FIGS. 10, 12 and 21 for cross-sectional views of the TFTportions as shown in FIGS. 21, 25 and 27 respectively, the basicprinciple of the Embodiment 2 as illustrated in FIGS. 5 and 6 adopts analignment control slit for determining the oblique direction of theliquid crystal molecules correctly, but Embodiment 1 cannot increase thestrength of electric field as Embodiment 1 does. Therefore, the responserate of Embodiment 2 is slower than that of Embodiment 1. In theapplication of displaying animations, it is appropriate to adoptEmbodiment 1 for the manufacture of LCD panels. From the planar views asshown in FIGS. 24 and 26, many metal wires are installed densely on thesame layer in Embodiment 1, and thus the existing short circuit problemmay occur easily. In addition to the short-circuit issue, the voltageapplied to the pixel electrode of Embodiments 1 and 2 is not 100%applied to the liquid crystal layer, and thus the shortcoming ofrequiring a higher driving voltage as shown in FIGS. 1 and 2 stillexists. Since the CF substrate can use a low-cost CF substrate which hasabout the same cost of TN, therefore the product competitiveness can beimproved. Particularly, it is not necessary to use a field order drivenLCD panel of the CF substrate, which must align the upper and lowersubstrates as shown in FIGS. 1 and 2, but the present invention does notneed any manufacture on the substrate as shown in FIGS. 3 and 4. Sucharrangement simply needs to form a substrate with a transparentelectrode film, and requires no adjustment of alignment theoretically.

Referring to FIGS. 28 to 31 for planar views of the TFT substrate inaccordance with Embodiment 3 of the present invention and FIG. 32 for acircuit model of the TFT substrate of the invention, a basic unit pixelis divided by the video signal line into two sub pixels: sub pixel A andsub pixel B. The ratio of areas of the sub pixel A to the sub pixel B isapproximately equal to 1:2. FIG. 34 shows a driving signal waveform ofan LCD panel in accordance with Embodiment 3 of the present invention.Even though the data is obtained from the same video signal line, thephase is changed by different common electrode as shown in FIG. 34,since each pixel electrode is combined with a capacitor of a differentcommon electrode, and a horizontal period (H period) is applied, and thewaveform of a signal with an opposite polarity maintains the effectivevoltage of the sub pixel A greater than the effective voltage of the subpixel B. FIG. 33 shows the quantity of light transmission of the LCDpanel when the signal waveform is driven, and the threshold voltage ofthe liquid crystals of the sub pixel A and the sub pixel B can bechanged for correcting y.

FIG. 83 shows the process of manufacturing the TFT substrates asillustrated in FIGS. 28 to 31, and FIG. 82 illustrates Embodiments 1 and2. A common electrode is manufactured in the first the photolithographicprocedure. In Embodiment 3 as shown in FIG. 32, it is not necessary toarrange the video signal line in parallel with the common electrode, andthus the common electrode is manufactured by the third photolithographicprocedure as shown in FIG. 83.

FIG. 35 shows a circuit model of the TFT substrate when a high-precisionsuper large LCD panel is manufactured. FIGS. 36 to 39 show the method ofdriving a TFT substrate as illustrated in FIG. 35. FIGS. 36 to 39 relateto the field order driving method. Since the display screen is dividedinto two: an upper screen and a lower screen, therefore the video signalline is also divided into two: an upper video signal line and a lowervideo signal line, and the video signals of the same polarity areapplied.

The common electrode has not been divided into two, but both upper andlower portions integrated. FIGS. 36 and 38 show that video signals arewritten from the center of the screen to the upper and lower screens inorder to prevent the blocks of the upper and lower screens from beingseparated. FIGS. 37 and 39 show that video signals are written from theupper and lower screens to the center of the screen. To divide thedisplay screen into two, the horizontal scan period is extended to twotimes of 2H. FIGS. 36 and 37 show that the horizontal scan period isdivided into two, such that different video signals can be written fortwo pixels by two different multitasking methods. FIGS. 38 and 39 showthat the horizontal scan period is divided into three, such thatdifferent video signals can be written for three pixels by threemultitasking methods.

Referring to FIGS. 53 and 45 for a planar view and a cross-sectionalview of an IPS TFT substrate in accordance with Embodiment 4 of thepresent invention, and FIG. 84 for the manufacturing process of an IPSTFT substrate in accordance with Embodiment 4 of the present invention,three times of photolithographic procedure adopting three times ofhalftone exposure method are conducted. FIG. 46 shows a circuit model ofa TFT substrate as illustrated in FIG. 53. The center of a pixel and thevideo signal are arranged in parallel with the common electrode. FIG. 56shows a circuit model of a TFT substrate when a high-precision supperlarge LCD panel is manufactured. FIG. 55 shows a driving waveformdiagram of a TFT substrate as illustrated in FIG. 56. Signal waveformsof different polarities are applied on even-numbered rows andodd-numbered rows, and signal waveforms of different polarities areapplied to the even-numbered rows and odd-numbered row of video signalwaveforms, and a signal with an opposite polarity is applied to thecommon electrode of each corresponding video signal line.

Even the modes of liquid crystals are different, the circuit models ofthe common electrode and the video signal line is identical to those asshown in FIG. 35. The IPS TFT substrate as shown in FIG. 56 can alsoadopt the same field order driving method of Embodiment 3. Similar tothe process as shown in FIG. 35, the process as shown in FIG. 56 dividesthe display screen into two: an upper screen and a lower screen, andthus the video signal line is also divided into two: an upper videosignal line and a lower video signal line, and the polarity of videosignals are the same.

The common electrode has not been divided into two, but it is connectedfrom top to bottom as a whole. To prevent the blocks of upper and lowerscreens from being separated, the video signals are written from thecenter of the screen upward or downward, or the video signals arewritten from the top or bottom of the screen towards the center of thescreen. The driving method for the scan lines is identical to that ofEmbodiment 3.

Referring to FIGS. 54 and 44 for a planar view and a cross-sectionalview of a FFS TFT substrate in accordance with Embodiment 5 of thepresent invention respectively, FIG. 47 for a cross-sectional view of aportion of a thin film transistor, and FIG. 85 for the manufacturingprocess of a FFS TFT substrate in accordance with Embodiment 5 of thepresent invention, the photolithographic procedure is conducted forthree times, and a halftone exposure method is applied for all of thethree times. The three times of Embodiments 4 and 5

3 use the halftone exposure method as shown in FIG. 66. Unlike thevertical alignment LCD panel, a horizontal electric field panel requiresdifferent orientation processing procedure (such as the frictionprocessing). To prevent having a poor alignment area, it is necessary tominimize the roughness of the TFT substrate. However, the planar viewsof FIGS. 53 and 54 show that the thickness of electrodes is increase tolower the resistance of a common electrode at the center of the screen.

Since a poor alignment area as shown in FIG. 66 must occur in both IPSand FFS modes, therefore the shortcoming of unable to show the blackcolor for a black potential exists. To minimize the poor alignment area,it is necessary to apply the halftone exposure method for three times.

FIGS. 61 and 62 use the manufacturing process as illustrated in FIG. 85,the process of the halftone exposure method is applied for one time, andany one can be selected. FIG. 63 illustrates the process of applying thehalftone exposure method for the second time, and FIG. 64 illustratesthe process of applying the halftone exposure method for three times,and FIG. 65 illustrates the process of performing the photolithographicprocedure for four times for manufacturing the FFS TFT substrate. Thehalftone exposure method is applied for two times.

Even if the FFS TFT substrate as shown in FIG. 54 adopts the samedriving method as the IPS TFT substrate as shown in FIG. 53, all circuitmodels of the TFT substrate as shown in FIG. 56 can be applicable forthe FFS mode of FIG. 54. If the driving method of FIG. 55 is used, theFFS mode with a high driving voltage can be driven easily. Since the FFSmode can produce a strong electric field, therefore the response rate ofthe liquid crystal molecules is smaller than that of the IPS mode andapplicable for the field order driving method. Particularly, a highvoltage can be applied to the LCD panels as shown in FIGS. 55 and 56,and thus such method is considered as a driving method applicable forhigh-speed operations, and most suitable for the field order drivingmethod for the divided upper and lower screens as shown in FIGS. 36 to39.

1. A method of fabricating FFS active matrix substrate, and saidsubstrate constituting an active matrix display device, characterized inthat: said substrate is fabricated by applying a photolithographicprocedure for three times: (1) forming a gate electrode, a pixelelectrode and a contact pad in said pixel electrode (wherein a firsttime of applying said photolithographic procedure adopts a halftoneexposure method); (2) forming a separate thin film semiconductor layercomponent, and a contact hole (wherein a second time of applying saidphotolithographic procedure adopts a halftone exposure method); and (3)forming a source electrode (or a video signal line), a drain electrode,a common electrode at the center of a pixel and a comb common electrode(wherein a third time of applying said photolithographic procedureadopts a halftone exposure method), such that after an ohmic contactlayer of a channel portion of said thin film transistor is dry etched, apartial film of a passivation layer is formed by a silicon nitride filmby using a mask deposition method (wherein said film is formed at aterminal portion other than those of a gate electrode, a sourceelectrode and a common electrode).
 2. A horizontal electric field activematrix liquid crystal display apparatus, manufactured by a method ofclaim
 1. 3. A FFS active matrix liquid crystal display apparatus,manufactured by a method of claim 1, characterized in that: an upperlayer of a pixel electrode at a position proximate to the center of apixel installs a common electrode in parallel with a video signal lineby an insulating film, and a signal voltage is applied to odd-numberedrows and even-numbered rows of said common electrode in a horizontalscan period (H period) and having opposite polarities with each other,and said polarities are opposite to the polarities of said video signalline within said horizontal scan period (H period, and said video signalline of said screen is divided into two at the middle of said displayscreen, and the signals at said upper and lower video signal line havethe same polarity, and said common electrode disposed at the center ofsaid pixel integrates said display screen from top to bottom as a whole.